| dc.identifier.uri | http://hdl.handle.net/11401/76481 | |
| dc.description.sponsorship | This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree. | en_US |
| dc.format | Monograph | |
| dc.format.medium | Electronic Resource | en_US |
| dc.language.iso | en_US | |
| dc.publisher | The Graduate School, Stony Brook University: Stony Brook, NY. | |
| dc.type | Dissertation | |
| dcterms.abstract | Neutral sphingomylinase-2 (nSMase2) is a ceramide-generating enzyme that has been implicated in growth arrest, apoptosis and exosome secretion. In this thesis, we show that doxorubicin induces a dose-dependent induction of nSMase2 mRNA and protein levels concomitant with an increase in neutral sphingomyelinase activity and ceramide levels. This induction appears to be specific to agents that inhibit topoisomerase I as well as those that produce single stranded DNA breaks. Upregulation of nSMase2 was dependent on ATR, Chk1 and p53, thus placing it downstream of the DNA damage pathway. Evidenced by knockdown studies, nSMase2 appears to play a protective function as its knockdown sensitizes cells to doxorubicin. Elucidating that mechanism, nSMase2 appears to regulate a transient S phase checkpoint through its prolongation. Its knockdown results in an earlier recovery from S phase arrest. Consistent with its function as a checkpoint regulator, we find that nSMase2 localizes to the nucleus following doxorubicin treatment and is housed in distinct subnuclear granules termed nuclear speckles. Interestingly, a specific lipid, C18:1 ceramide appears to be the major product of nSMase2 regulating its biology. Overexpression of nuclear targeted bacterial sphingomyelinase or exogenous media supplementation with oleate rescues the cells from doxorubicin-induced cell death. Using a phosphoproteomics approach, we determined possible phosphorylation targets of nSMase2. This revealed the cohesin complex as a major downstream target of nSMase2. Taken together, these studies demonstrate the essential role of nSMase2 in DNA damage-induced S phase arrest through the regulation of the cohesion complex | |
| dcterms.available | 2017-09-20T16:50:23Z | |
| dcterms.contributor | Hannun, Yusuf | en_US |
| dcterms.contributor | Del Poeta, Maurizio | en_US |
| dcterms.contributor | Badhuri-Mcintosh, Sumita | en_US |
| dcterms.contributor | Hearing, Patrick | en_US |
| dcterms.contributor | Miller, Todd. | en_US |
| dcterms.creator | Shamseddine, Achraf | |
| dcterms.dateAccepted | 2017-09-20T16:50:23Z | |
| dcterms.dateSubmitted | 2017-09-20T16:50:23Z | |
| dcterms.description | Department of Molecular and Cellular Biology. | en_US |
| dcterms.extent | 228 pg. | en_US |
| dcterms.format | Monograph | |
| dcterms.format | Application/PDF | en_US |
| dcterms.identifier | http://hdl.handle.net/11401/76481 | |
| dcterms.issued | 2015-05-01 | |
| dcterms.language | en_US | |
| dcterms.provenance | Made available in DSpace on 2017-09-20T16:50:23Z (GMT). No. of bitstreams: 1
Shamseddine_grad.sunysb_0771E_12540.pdf: 4481735 bytes, checksum: 7a8afc95f24a536d541d7cfbc82d7896 (MD5)
Previous issue date: 2015 | en |
| dcterms.publisher | The Graduate School, Stony Brook University: Stony Brook, NY. | |
| dcterms.subject | Ceramide, checkpoint, doxorubicin, p53, Sphingomyelinase | |
| dcterms.subject | Biology | |
| dcterms.title | Role and regulation of neutral sphingomyelinase-2 in response to DNA damage | |
| dcterms.type | Dissertation | |
